An Improved Adjusted Plus-Minus Statistic for NHL Players

Abstract: The plus-minus statistic for NHL players is meant to be a measure of a player’s offensive and defensive abilities. However, a player’s plus-minus is highly dependent on the team he plays for, the opponents he faces, and other variables out of his control, so it’s not always a good measure of that player’s individual contribution to his team. In this paper we develop an adjusted plus-minus statistic that attempts to isolate a player’s individual contribution. Using data from the detailed shift reports on NHL.com, we develop two weighted least squares regression models to estimate an NHL player’s effect on his team’s success in scoring and preventing goals, independent of that player’s teammates and opponents. Our initial work focused on even strength situations, excluding situations in which one team had pulled their goalie. In our current work, we have modeled power play and shorthanded situations, and we are able to estimate a player’s offensive and defensive contributions during those situations. Also, for those shifts that begin with a faceoff, we have accounted for the zone on the ice in which a shift begins.